1. Field of the Invention
This invention relates to a reciprocating compressor, such as a swash plate compressor, a wobble plate compressor, and an in-line compressor (crank compressor).
2. Description of the Prior Art
The present assignee proposed a reciprocating compressor (swash plate compressor) in Japanese Laid-Open Patent Publication (Kokai) No. 9-4563 (corresponding to U.S. Pat. No. 5,709,535).
The proposed swash plate compressor includes a cylinder block having a plurality of compression chambers formed therein, a cylinder head which is secured to the cylinder block and has a discharge chamber and a suction chamber formed therein, a valve plate arranged between the cylinder block and the cylinder head for separating the compression chambers from the discharge chamber and the suction chamber, refrigerant outlet ports via which refrigerant gas is delivered from the compression chambers to the discharge chamber, refrigerant inlet ports via which refrigerant gas is drawn from the suction chamber into the compression chambers, discharge valve:; for opening and closing the refrigerant outlet ports, suction valves for opening and closing the refrigerant inlet ports, and stoppers for each setting a proper limit to an amount of opening or resilient deformation of a corresponding one of the discharge valves.
FIG. 1 shows a valve plate, a valve sheet, and a stopper plate of another conventional reciprocating compressor (swash plate compressor) of this type, in an exploded state, which is proposed by the present assignee in Japanese Patent Application No. 9-14665, while FIG. 2 is a plan view of the stopper plate of the proposed compressor in a state in which the valve plate, the valve sheet, and the stopper plate are assembled. FIG. 3 is a partially sectional view taken on line III--III of FIG. 2.
In the proposed reciprocating compressor, the discharge valves are formed by the valve sheet 327 and a plurality of discharge valve elements 327a integrally provided thereon, while the suction valves are formed by the same valve sheet 327 and a plurality of suction valve elements 327d integrally provided thereon. The discharge valve elements 327a and the suction valve elements 327d are each provided by cutting a portion of the valve sheet 327 into a tongue shape.
The stoppers are formed by the stopper plate 329 arranged between the valve sheet 327 and the cylinder head 304, and a plurality of stopper portions 329a which are each formed by cutting a portion of the stopper plate 329 opposed to a corresponding one of the discharge valve elements 327a. The stopper plate 329 is also formed therethrough with the refrigerant inlet ports 329d as well as a plurality of slots 329b each open to the discharge chamber 324 for communicating between the discharge chamber 324 and a corresponding one of the refrigerant outlet ports 303a.
The valve plate 303 is formed with the refrigerant outlet ports 303a as well as a plurality of relief holes 303b each open to a corresponding one of the compression chambers 321 for communicating between the compression chamber 321 and a corresponding one of the refrigerant inlet ports 329d.
Since, as described above, the proposed compressor employs the valve sheet 327 formed with the plurality of discharge valve elements 327a and suction valve elements 327d as well as the stopper plate 329 formed with the plurality of stopper portions 329a, component parts are reduced in number, and moreover, the valve plate 303, the valve sheet 327, and the stopper plate 329 can be simply placed on the cylinder block, one upon another, when they are assembled to the cylinder block, which markedly facilitates assembly of the compressor.
A problem with the compressor is that the valve plate 303 is deformed or distorted toward the compression chamber 321 during each suction stroke due to a difference in pressure between the discharge chamber 324 and the compression chamber 321, and if the amount of deformation of the valve plate 303 becomes large, high-pressure refrigerant gas delivered to the discharge chamber 324 flows back to the compression chamber 321, which results in degraded performance of the compressor.
A solution to the problem of the back flow of refrigerant gas is to increase the thickness of the valve plate 303 so as to increase the rigidity of the valve plate 303.
However, if the thickness of the valve plate 303 is increased, volumes of the refrigerant outlet ports 303a and the relief holes 303b become larger to increase dead volume, causing degradation of volumetric efficiency of the compressor.